Magainins are 23 residue peptides originally found in frog skin that are potent broad spectrum antibiotics. As a new class of antibiotics they are subject to a broad range of biophysical investigations. In collaboration with M. Zasloff, who originally identified these peptides, we have been studying their structures in a variety of membrane environments, especially in oriented lipid bilayers by solid-state NMR spectroscopy. These peptides are an interesting system in their own right, and provide an excellent model system for developing methods generally applicable to membrane proteins. Structural models are being refined through improved measurements on specifically labeled proteins. Uniformly 15N labeled maginin peptides should be available shortly.